This invention relates to telephony and, more particularly, to a four-wire telephone system for private line communications among plural users, specifically known as a "hoot-and-holler" system providing full duplex conference-type communication.
In certain business segments, there is a need for conference-type communication networks wherein all users of the system, whether at a central or various possible remote locations, will simultaneously be provided with instant access to all communications taking place on the system, being both able to receive as well as to transmit messages of interest to users of the system. This is particularly true of stock and commodities brokerages which typically have a central facility as well as numerous branch locations, some of which may be located in states far distant from the central office or facilities. Such a conference-type system is utilized not only for delivering messages from the central facilities of interest relative to the marketing of stocks and other securities, but also permits users at the different remote locations to interrogate and discuss brokerage matters with one or more departments at the central offices or with facilities at a different remote location. Heretofore, such systems have made utilization of existing four-wire telephone circuits, such as have included not only local telephone lines operated by local telephone companies but also long distance or "long lines" telephone circuits.
Until the recent development of private long distance carriers and the divestiture by the major long distance carrier of its local telephone companies, it was typical for a single telephone company to be responsible for all telephone facilities, including not only local telephone facilities and telephone lines on the customer's premises, but also long distance lines. A major consequence of these developments has been that individual telephone customers have become primarily responsible for all telephone equipment and lines which are on their premises. Thus, it now is typical for local telephone companies to require that the user maintain at his own expense such local equipment and the various on-premises telephone wiring such as line cords which link telephone instruments to telephone company points of connection. For such on-premises wiring, the customer is responsible.
If the user of an instrument in such a system experiences difficulty with the system, ordinarily such user will not be able to determine whether the fault lies within the existing telephone lines, such as the long distance circuit, or other line facilities provided by telephone companies or is instead the fault of the equipment or service connections which are the user's responsibility. If the latter, a service call by the telephone company to determine that the fault is a matter of user responsibility will result in a relatively high service call charge. If, on the other hand, the user had the capability in advance to determine that the fault lies within the equipment and service connections which are the responsibility of the telephone company, such user would be able to avoid the imposition of such expensive service expenditures. In a so-called "hoot-and-holler" system involving numerous instruments at various localities, needless service call charges can amount to a very substantial expenditure.
It is an object of the present invention to provide a four-wire "hoot-and-holler" telephone system of improved facility and simplicity, providing numerous functional and commercial advantages and ease of use.
It is a further object of the present invention to provide such a telephone system which allows the user at any of various locations to provide a self-test mode of usage which will readily and promptly allow even a technically unskilled person to ascertain whether the fault is in equipment and service connections which are the responsibility of the user, or instead is within the facilities or equipment maintained and required to be serviced by a telephone company.
Another object of the present invention is the provision of such a telephone system which employs a novel test set which can be utilized for carrying out self-testing operation by such an unskilled, untutored user in a facile, quickly implemented manner.
It is a further object of the invention to provide such a testset which is capable of extrinsic use as a stand-alone telephone instrument for conventional use, stand-by or temporary use in a location serviced by the system, as where an existing repeater of the system or other related equipment must be taken out of service as for repairs, or is not yet installed.
Another object of the invention is the provision of such a system having relatively few components which are simply and easily installed at a desired location and which includes components which are not of a critical nature and thus will reliably operate immediately upon installation.
Among still other objects of the invention may be noted the provision of such a system having telephone instruments which are reliable and long lasting in usage as well as offering convenience and flexibility of usage, together with ease of adjustment for all operating conditions.
Briefly, a four-wire "hoot-and-holler" telephone system according to the present invention provides full duplex conference communication among all users of this system including one or more users at different locations interconnected by an existing four-wire telephone circuit such as conventional long distance lines to provide thereby a private line system capable of providing high quality conference call intercommunication among all users of the system. The system provides four-wire desksets for individual users. Each
Individual deskset includes a deskset console including a speaker for audibly transmitting to the surrounding area all incoming communications and transmissions not originated by the user of the deskset. The deskset includes also a handset including a transmitter for permitting selective origination of outgoing transmissions by the user as well as a conventional handset receiver. desksets as well as any so-called system orators (which provide only a monitoring function) are interconnected with repeaters at the individual locations. The repeaters provide transformer isolation of the desksets with respect to the telephone lines as well as incoming and outgoing amplification.
Included in this system at the different locations are four-wire testsets adapted for connection to the existing telephone circuits in lieu of the repeater and the four-wire desksets.
Each such testset includes a testset console including a speaker like those of the desksets, and similarly includes also a handset with a handset receiver and handset transmitter. Self-test features of the testset permit its user to cause reproduction by the speaker of the testset console of outgoing transmissions as well as substitution by the testset of the repeater and the deskset functions. Accordingly, the testset provides user assurance of proper operation of system components, circuits and line cords and the like at the remote location, and whereby the existence and location of a fault in the system may be readily ascertained, and thereby revealing to the user whether the fault is one which the user is responsible for correcting or whether instead is a fault which is the responsibility of the telephone company, for example, which owns and maintains the existing telephone circuit.
Other objects and features will be in part apparent and in part pointed out hereinbelow.